Eupera troglobia sp. nov.: the first troglobitic bivalve from the Americas (Mollusca, Bivalvia, Sphaeriidae)

Eupera troglobiasp. nov. is the first fully described troglobitic bivalve discovered in the Americas, and possibly the second in the world. The troglobitic designation is based on the lack of pigmentation, reduction in size and shell thickness, and large and few offspring. Unlike its relatives that live in the roots of the water hyacinth, this new species is attached to the walls of the caves with a byssus. The anatomical study shows some peculiarities in comparison with the congeners, especially the simplicity of the foot, the siphons and the gut. This discovery is a new contribution to the efforts for the conservation of subterranean habitats in Brazil.